Can't connect to remote instance via ssh tunneling + proxying

Question

Having trouble connecting to remote server via ssh tunneling.

I'm not that experienced with ssh or portforwarding. I'm trying to forward traffic from an application on a remote lab server to a port on my laptop so I can monitor the traffic. I can log into the server without a problem using:

ssh -i ~/.ssh/mykey.pem username@server.com

However, when I try to create a tunnel (which I am routing through a proxy server via SwitchyOmega):

ssh -L 3128:localhost:8888 -N -i ~/.ssh/mykey.pem username@server.com 

I still can't access the page.

My OS is El Capitan and I'm using Chrome, but the remote server is running ubuntu. I appreciate any advice or suggested reading!

EDIT: Initially thought the server was on AWS with a fixed IP, but it turns out its a physical lab server.

Answer 1

In a new terminal window on your local machine, SSH into the remote machine using the following options to setup port forwarding.

ssh -N -L 3128:localhost:8888 user@remote_server

-N options tells SSH that no commands will be run and it’s useful for port forwarding, and -L lists the port forwarding configuration that we setup.

To close the SSH tunnel simply do ctrl-c.

Answer 2

You need to create the fowarding accessible by others, therefore do not bind localhost, but the external IP or *. Also you need to specify the -g switch, if you are connecting to the forwarded port remotely:

ssh -g -L *:3128:localhost:8888 -N -i ~/.ssh/mykey.pem username@server.com